AUTHOR=Gong Sanqiang , Chai GuangJun , Xiao Yilin , Xu Lijia , Yu Kefu , Li Jinlong , Liu Fang , Cheng Hao , Zhang Fengli , Liao Baolin , Li Zhiyong 

TITLE=Flexible Symbiotic Associations of Symbiodinium With Five Typical Coral Species in Tropical and Subtropical Reef Regions of the Northern South China Sea

JOURNAL=Frontiers in Microbiology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2018.02485

DOI=10.3389/fmicb.2018.02485

ISSN=1664-302X

ABSTRACT=<p>The coral symbiont <italic>Symbiodinium</italic> plays important roles in the adaptation of coral to environmental changes. However, coral-<italic>Symbiodinium</italic> symbiotic associations are not well-understood in the South China Sea (SCS) whilst considering environmental factors and host taxa. In this study, next-generation sequencing of the internal transcribed spacer region 2 (ITS2) marker gene was used to explore the symbiotic associations between <italic>Symbiodinium</italic> and five typical coral species across tropical and subtropical reef regions of the SCS. The results showed that <italic>Acropora</italic> sp., <italic>Galaxea fascicularis</italic>, <italic>Platygyra lamellina</italic>, and <italic>Sarcophyton glaucum</italic> exhibited distinct <italic>Symbiodinium</italic> compositions between tropical and subtropical reef regions, whereas <italic>Porites lutea</italic> had stable <italic>Symbiodinium</italic> compositions. More heterogeneous <italic>Symbiodinium</italic> compositions among different coral species were observed in the tropical region, but there were no statistically significant differences in <italic>Symbiodinium</italic> compositions among different coral species in subtropical reef regions. There was a correlation between the <italic>Symbiodinium</italic> compositions and environmental factors, except for the composition of <italic>P. lutea</italic>. <italic>Symbiodinium</italic> subclades D1, D2, C71, C71a, C21, C3b, and C161 were primarily explained by the seawater temperature, nitrate, ammonia, and phosphate. Several host-specific <italic>Symbiodinium</italic> subclades (e.g., C15, C15.6, and C91) were observed in <italic>P. lutea</italic> as well. The findings of this study demonstrate the relationship of <italic>Symbiodinium</italic> diversity with coral hosts and the environment are helpful for elucidating the adaptation of corals to global climate change and anthropogenic disturbance.</p>